It has been common to provide a dash pot to control the closing of an automobile throttle during the latter part of the movement as the throttle approaches the idle position after the driver takes his foot off the gas pedal. Typical dash post are shown in U.S. Pat. Nos. 2,657,038, 2,862,702 and 2,894,740.
It has been proposed to control the return of the throttle to idle position from the fully open position throughout its movement in order to stabilize power train torque.
Accordingly among the objectives of the present invention are to provide a dash pot which can be present with a carburetor for controlling the movement of the throttle from a full throttle position to an idle position; which dash pot can be attached directly to the throttle linkage; which will provide the required dampening of the movement of the throttle; which will permit thermal variation without pressure build-up; and which will obviate the need for the conventional throttle return spring.
In accordance with the invention, the dash pot incorporates a cylinder, guide member and associated shaft, the shaft being connected directly to the throttle linkage and a spring urging the shaft inwardly to close the throttle. A chamber and associated diaphragm are provided in communication with the cylinder and the chamber and cylinder are filled with an incompressible fluid. An orifice controls communication between the chamber and the cylinder and a check valve meters the flow of the fluid between the cylinder and chamber so that the movement of the shaft is dampened as the shaft is moved inwardly and the shaft is permitted less restricted free movement outwardly against the action of the spring.